The present invention relates to false-twisting systems and, more particularly, to a false-twisting system furnished with a false twister of a type having intercrossing and interengaging endless belts.
One type of known false-twisting apparatus employs two endless belts which intercross each other to nip filament yarns therebetween, as disclosed for example in U.S. Pat. No. 3,045,416. The endless belts of this type of apparatus are spaced slightly away from each other to avoid wear of the working surfaces of the belts. Another type of false twister is proposed in my U.S. Pat. No. 4,047,373 in which two intercrossing endless belts each having a small coefficient of friction are urged in surface-to-surface relation against each other to nip and false-twist filament yarns therebetween. However, such a false twister using interengaging endless belts involves a certain degree of wear of the belts and generation of heat. Particularly, an increase in the contact or nipping pressure between the belts produces an increase in the temperature of the belts due to friction, so that heat-setting provided to false-twisted filament yarns tends to be removed and/or the belt surfaces tend to smoke end be damaged. Though permitting a considerable velocity of yarn feed, the false twister of the second-mentioned type needs a disproportionately long cooling zone to cope with such a yarn velocity.